there are many possibilities to consider:
1. preparing for a quilt show is a huge undertaking. in all the rush and hubub they may be neglecting their emails, etc.
that would not be a valid excuse for blowing you off.
2. they may have read your email and responded, but your mail handler sent it straight to spam.
3. your email to them may not have arrived.
4. whoever provided the service you found displeasing may have been the one to read the email and decided to keep her boss in the dark about it.
so ... the developments so far could indicate a lack of concern on their part, or a series of coincidental factors that have gotten in the way of communication with the shop's owner/manager.
by not taking the opportunity to speak to her in person you passed up your very best chance to know she's aware of the problem and you denied her the ideal opportunity to fix it.